I am running into an issue with .IES lighting. The top image shows how the light distribution should look when looking straight down from above the light. The second image shows what the light looks like in UE4. The light distribution changes when switching out .IES files however none of them take on the expected distribution. It is important for us to be able to see the exact light distribution as it is shown in the top image. Is UE4 incompatible with certain .IES types? Any suggestions would be helpful. Thanks a lot.
Hi -
In UE4, IES profiles are not calculated dynamically / mathematically as they are in other rendering software. IES profiles are calculated once on import and converted into a texture file. This method is extremely performance friendly but does generate a problem when looking at the reflections generated by the light source, since the light source is still mathematically a sphere light. There is currently a bug report in to fix this issue with the IES profiles.
Thank You -
Hi, Eric.
I am having the exact same problem. I am using 4.18. Do you know if it is a bug, it can’t be that they’ve still not fixed it? Do you maybe know if there is something else causing this inaccuracies in the .ies profile?